8.0以下版本

#允许所有用户远程访问 修改用户名和密码为你自己的
mysql> GRANT ALL PRIVILEGES ON *.* TO 'USERNAME'@'%' IDENTIFIED BY 'PASSWORD' WITH GRANT OPTION;
#允许单个ip 修改用户名和密码为你自己的
mysql> GRANT ALL PRIVILEGES ON *.* TO 'USERNAME'@'1.2.3.4' IDENTIFIED BY 'PASSWORD' WITH GRANT OPTION;
#最后 mysql> FLUSH PRIVILEGES;

8.0版本

mysql> CREATE USER 'root'@'%' IDENTIFIED BY 'root';
## 语法模版 GRANT ALL PRIVILEGES ON 库名.表名 TO '用户名'@'IP地址' WITH GRANT OPTION;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;